The placenta is a structure that develops in the uterus during pregnancy to nourish the growing baby. If the placenta peels away from the inner wall of the uterus before delivery — either partially or completely — it's known as placental abruption. Placental abruption can deprive the baby of oxygen and nutrients and cause heavy bleeding in the mother.

Placental abruption often happens suddenly. Left untreated, placental abruption puts both mother and baby in jeopardy.

Placental abruption is most likely to occur in the last trimester of pregnancy, especially in the last few weeks before birth. Classic signs and symptoms of placental abruption include:

Vaginal bleeding

Abdominal pain

Back pain

Uterine tenderness

Rapid uterine contractions, often coming one right after another

Abdominal pain and back pain often begin suddenly. The amount of vaginal bleeding can vary greatly, and doesn't necessarily correspond to how much of the placenta has separated from the inner wall of the uterus. It's even possible to have a severe placental abruption and no visible bleeding, if the blood becomes trapped inside the uterus by the placenta.

In some cases, placental abruption develops slowly. If this happens, you might notice light, intermittent vaginal bleeding. Your baby might not grow as quickly as expected, and you might have low amniotic fluid (oligohydramnios) or other complications.

When to see a doctor

Seek emergency care if you experience any classic signs or symptoms of placental abruption, including:

Vaginal bleeding

Abdominal pain

Severe back pain

Rapid uterine contractions

The specific cause of placental abruption is often unknown. Possible causes include trauma or injury to the abdomen — from an auto accident or fall, for example — or rapid loss of the fluid that surrounds and cushions the baby in the uterus (amniotic fluid).

Various factors can increase the risk of placental abruption, including:

High blood pressure. High blood pressure — whether chronic or as a result of pregnancy — increases the risk of placental abruption.

Abdominal trauma. Trauma to your abdomen — such as from a fall or other type of blow to the abdomen — makes placental abruption more likely.

Substance abuse. Placental abruption is more common in women who smoke or use cocaine during pregnancy.

Premature rupture of the membranes. During pregnancy, the baby is surrounded and cushioned by a fluid-filled membrane called the amniotic sac. The risk of placental abruption increases if the sac leaks or breaks before labor begins.

Multiple pregnancy. If you're carrying more than one baby, the delivery of the first baby can cause changes in the uterus that trigger placental abruption before the other baby or babies are delivered.

Maternal age. Placental abruption is more common in older women, especially after age 40.

Placental abruption can cause life-threatening problems for both mother and baby.

For the mother, placental abruption can lead to:

Shock due to blood loss

Blood clotting problems (disseminated intravascular coagulation)

The need for a blood transfusion

Failure of the kidneys or other organs

For the baby, placental abruption can lead to:

Deprivation of oxygen and nutrients

Premature birth

Stillbirth

After the baby is born, bleeding from the site of the placental attachment is likely. If the bleeding can't be controlled, emergency removal of the uterus (hysterectomy) might be needed.

Placental abruption is often a medical emergency, leaving you no time to prepare. However, it's possible that your health care provider might notice signs of an impending abruption before an emergency situation develops. Depending on the suspected severity of your placental abruption, you might be admitted to the hospital and monitored — or you might be admitted for emergency surgery to deliver the baby.

If you and the baby are being monitored in the hospital, here's some information to help you prepare for what's to come, and what to expect from your doctor.

What you can do

While you're in the hospital:

Pay attention to changes. Alert your health care team immediately if there's a change in your symptoms or their frequency.

List all medications you've been taking, including vitamins and supplements. Be sure to let your doctor know if you've smoked during your pregnancy or used illegal drugs.

Ask a loved one or friend to be with you, if possible. Sometimes it can be difficult to remember all of the information provided, especially in an emergency situation. Someone who's with you might remember something that you missed or forgot.

A loved one can also help you keep track of the questions you have for your doctor to make sure you don't forget to ask something that's important to you. Some basic questions you might want to ask your doctor include:

What kinds of tests do I need? How do I prepare for these tests?

Is the baby in any danger? Am I in any danger?

What are the treatment options?

What are the possible complications?

What can I expect if the baby is born now?

Will I need a blood transfusion?

What are the chances that I might need a hysterectomy after the delivery?

What to expect from your doctor

Your doctor is likely to ask you a number of questions. For example:

When did you first begin experiencing signs and symptoms?

Have you noticed any changes in your signs and symptoms?

How much bleeding have you noticed?

Can you feel your baby moving?

Have you noticed any clear fluid leaking from your vagina?

Have you had any nausea, vomiting or lightheadedness?

Are you having contractions? If so, how close together are they?

If your health care provider suspects placental abruption, he or she will do a physical exam to check for uterine tenderness or rigidity. To help identify possible sources of vaginal bleeding, you might need blood tests or an ultrasound.

During an ultrasound, high-frequency sound waves are used to create an image of your uterus on a monitor. It's not always possible to see a placental abruption on an ultrasound, however.

It isn't possible to reattach a placenta that's separated from the wall of the uterus. Treatment options for placental abruption depend on the circumstances:

The baby isn't close to full term. If the abruption seems mild, your baby's heart rate is normal and it's too soon for the baby to be born — generally before 34 weeks of pregnancy — you might be hospitalized for close monitoring. If the bleeding stops and your baby's condition is stable, you might be able to rest at home. In some cases, you might be given medication to help your baby's lungs mature, in case early delivery becomes necessary.

The baby is close to full term. If your baby is almost full term — generally after 34 weeks of pregnancy — and the placental abruption seems minimal, a closely monitored vaginal delivery might be possible. If the abruption progresses or jeopardizes your health or your baby's health, you'll need an immediate delivery — usually by C-section. If you experience severe bleeding, you might need a blood transfusion.

You can't directly prevent placental abruption, but you can decrease certain risk factors that make placental abruption more likely. For example, don't smoke or use illegal drugs, such as cocaine. If you have high blood pressure, work with your health care provider to control the condition.

If you've had any kind of abdominal trauma — from an auto accident, fall or other injury — seek immediate medical help because of the increased risk of placental abruption and other complications.

If you've had a placental abruption and are planning another pregnancy, talk to your health care provider to see if there are any ways you might be able to reduce the risk of another abruption before conceiving again. Expect your health care provider to carefully monitor your condition throughout the pregnancy.

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